Help!! I have a sudden "mystery" hum from my EP500
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Joined: Dec 2004
Posts: 93
old hand
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OP
old hand
Joined: Dec 2004
Posts: 93 |
Been enjoying my EP500 for a year now w/no issues. All of a sudden when I turn it on now, I get a very low level faint hum. When I turn the Yamaha Receiver on the hum intensifies quite a bit. I know this sounds like a ground loop, but NOTHING has changed w/my equipment and all connections seem firm? When I unplug the RCA cable from the receiver to the sub, but leave the power on the sub, the hum completely disappears? What has happened?
Thanks guys!
M60
VP150
2x QS8
EP500
HK 7300
DENON DVD-3910
Sony 60" SXRD
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Re: Help!! I have a sudden "mystery" hum from my EP500
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Joined: Apr 2005
Posts: 1,155
connoisseur
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connoisseur
Joined: Apr 2005
Posts: 1,155 |
Do you have a dog or a cat that might have been chewing on the cable?
Try a different cable and see what happens.
The Rat.
M80s, VP-150, QS8s,
SVS PC 20-39+, OPPO,
Onkyo 703s, Harmony 880
Sony 60" SXRD HDTV
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Re: Help!! I have a sudden "mystery" hum from my EP500
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Joined: Jan 2002
Posts: 3,270
connoisseur
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connoisseur
Joined: Jan 2002
Posts: 3,270 |
darthkringle,
If the hum disappears from the EP500 when you unplug the coaxial sub cable, then there is nothing wrong with the EP500. Look on the back of the 500 for a Ground Screw. If you remove that, it may help.
Otherwise, you might have to insert a ground-lift transformer on your cable-TV input. Try disconnecting your cable or video antenna or satellite feed and see if the hum disappears. If it does, then that's the source of the ground loop.
Regards,
Alan Lofft, Axiom Resident Expert (Retired)
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Re: Help!! I have a sudden "mystery" hum from my E
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Joined: Dec 2004
Posts: 93
old hand
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OP
old hand
Joined: Dec 2004
Posts: 93 |
Alan- Thanks as always. Removing the Ground Screw did in fact help. Any ideas on why I would suddenly have a ground loop issue after a year and my equipment has not changed? Thanks!!
M60
VP150
2x QS8
EP500
HK 7300
DENON DVD-3910
Sony 60" SXRD
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Re: Help!! I have a sudden "mystery" hum from my E
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Joined: Jan 2004
Posts: 13,840 Likes: 13
shareholder in the making
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shareholder in the making
Joined: Jan 2004
Posts: 13,840 Likes: 13 |
that is a good question, I was going to mention the screw also as it is mentioned in the pamphlet that comes with the 500/600.
Do you have a surge/line conditioner in your setup, this may help.
Randy
M80s VP180 4xM22ow 4xM3ic EP600 2xEP350 AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85
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Re: Help!! I have a sudden "mystery" hum from my EP500
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Joined: Mar 2006
Posts: 95
old hand
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old hand
Joined: Mar 2006
Posts: 95 |
Alan,
What does this screw do? Seperate the amp from the mains ground? Does that make it 'float' and ground via the RCA to the AVR? I have to look - is there a screw on the 350?
This past weekend I had a hum problem with my EP350. I heard it regardless of whether the sub was on or not, and unplugging the RCA OR the power from the wall eliminated it. What I ended up doing was running an extension cord from the sub to the same surge suppressor/power strip my AVR is plugged in to. That fixed it, and i suspect the power strip isolated ground in some way. Now everything is plugged into the same strip.
-Brian
2xM60ti, 2xM3ti, 2xQS4, VP100, EP350, N2's
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Re: Help!! I have a sudden "mystery" hum from my EP500
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Joined: Jan 2002
Posts: 3,270
connoisseur
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connoisseur
Joined: Jan 2002
Posts: 3,270 |
n8wrl,
Something like you describe. Without asking Tom, our engineer, I'm not sure what it exactly does, but it does not endanger anyone in terms of electrical shock (like putting a "cheater" on a 3-way plug does). I don't think there is a ground-lift screw on the 350.
Glad you solved your problem.
Regards,
Alan Lofft, Axiom Resident Expert (Retired)
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Re: Help!! I have a sudden "mystery" hum from my E
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Joined: Jan 2002
Posts: 3,270
connoisseur
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connoisseur
Joined: Jan 2002
Posts: 3,270 |
darth,
Good. No idea why you suddenly got a ground-loop unless something subtle changed in your system. Perhaps you connected some video-related device or disconnected an aging VCR or something like that. Even a tiny shift in the ground potential will cause a hum.
Regards,
Alan Lofft, Axiom Resident Expert (Retired)
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Re: Help!! I have a sudden "mystery" hum from my E
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Joined: Sep 2005
Posts: 50
buff
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buff
Joined: Sep 2005
Posts: 50 |
Hi. I had a bad ground loop hum. Removing the "screw" didn't help much. I ended up buying a SUB1RR from Jenson to isolate the sub from the receiver. The SUB1RR was expensive, about $100US, but it got rid of the hum. I subsequently purchased a surge protector. It seems that the surge protector by itself also removes the hum.
Too bad I wasted the $100.
maphiker
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Re: Help!! I have a sudden "mystery" hum from my E
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Joined: Mar 2006
Posts: 95
old hand
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old hand
Joined: Mar 2006
Posts: 95 |
Yes - this is a common problem on computer sound cards as well. A simple 1:1 isolation transformer on the audio lines is all you really need - that was going to be my next try if the extension cord didn't fix it.
-Brian
2xM60ti, 2xM3ti, 2xQS4, VP100, EP350, N2's
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